WO1990013826A1 - Procede d'enregistrement de spectres de resonance de spins - Google Patents

Procede d'enregistrement de spectres de resonance de spins Download PDF

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Publication number
WO1990013826A1
WO1990013826A1 PCT/DE1990/000309 DE9000309W WO9013826A1 WO 1990013826 A1 WO1990013826 A1 WO 1990013826A1 DE 9000309 W DE9000309 W DE 9000309W WO 9013826 A1 WO9013826 A1 WO 9013826A1
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group
pulse
frequency
frequency pulse
sample
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PCT/DE1990/000309
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German (de)
English (en)
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Alexander KNÜTTEL
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Bruker Medizintechnik Gmbh
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Priority to DE59008513T priority Critical patent/DE59008513D1/de
Priority to EP90906133A priority patent/EP0422172B1/fr
Publication of WO1990013826A1 publication Critical patent/WO1990013826A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/483—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy
    • G01R33/4833—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/48—NMR imaging systems
    • G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
    • G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution

Definitions

  • the invention relates to a method for recording nuclear magnetic resonance spectra of samples with at least three groups of nuclei of the same core type, of which a first group is coupled to a second group, while a third group is uncoupled from the second group, but has a chemical shift which essentially only corresponds to that of the first group, the signal of the third group being suppressed for the sole representation of the signal of the first group.
  • the invention further relates to a method for recording nuclear magnetic resonance spectra of samples with at least three groups of nuclei, of which a first group of a first type of nucleus is coupled to a second group of a second type of nucleus, while a third group of the first type of nucleus is uncoupled from the second group , but has a chemical shift that only coincides essentially with that of the first group, the signal of the third group being suppressed for the sole representation of the signal of the first group.
  • the invention relates generally to a method for recording spin resonance spectra of samples with at least three groups of spins, a first group being coupled to a second group while a third group being uncoupled to the second group, but a signal having a spectral position which essentially only coincides with that of the first group, the signal of the third group being suppressed for the sole representation of the signal of the first group.
  • Differential measuring methods also have the fundamental disadvantage that, as a result of the subtraction of high interference signal amplitudes, measurement errors can occur which are in the same order of magnitude as the useful signal.
  • volume-selective nuclear magnetic resonance spectra is a known technique, examples can be found in the textbook by Wehrli, Felix W., Arthur Shaw and J. Bruce Kneeland "Bio-medical Magnetic Esonance I aging", Verlag Chemie, 1988, pages 1 to 45 and 521 to 545.
  • both coupling partners consist of the same nucleus, e.g. of protons (* H), while in the case of heteronuclearly coupled spin systems, the coupling partners belong to different nucleus types, e.g. the A group to the protons ( 1 H) and the X group a carbon isotope ( 13 C).
  • the invention is further illustrated using the simple example of scalar coupling (J), but it goes without saying that applications are also possible with other types of coupling, for example dipole coupling.
  • the invention is based on the object of developing a method of the type mentioned at the outset such that volume-selective measurements on biological samples, in particular on patients, are possible with a single pulse sequence.
  • this object is achieved according to the invention in that a pulse train of three high-frequency pulses, preferably 90 ° high-frequency pulses, is radiated onto the sample such that the second high-frequency pulse the magnetization of the cores of the first group is set to be transferred to the cores of the second group by means of polarization transfer,
  • a first gradient magnetic field pulse that dephases the cores of the second group is applied to the sample
  • the third high-frequency pulse is set in such a way that the magnetization of the cores of the second group is transferred back to the cores of the first group by means of polarization back transfer, and then a second gradient magnetic field pulse that is rephased for the cores of the first group is exercised on the sample.
  • the object on which the invention is based is achieved on the one hand by that a pulse sequence of five high-frequency pulses, preferably 90 ° high-frequency pulses, is irradiated onto the sample, that the second high-frequency pulse and a third high-frequency pulse are set such that the magnetization of the nuclei is an ⁇ of the first type of nucleus the first group belonging to the nucleus of the second group belonging to the second type of nucleus is transferred by means of polarization transfer,
  • a fourth high-frequency pulse and a fifth high-frequency pulse are set in such a way that the magnetization of the cores of the second group is transferred back to the cores of the first group by means of polarization retransfer, and then a phase that is rephasing for the cores of the first group, second gradient magnetic field pulse is applied to the sample.
  • a pulse train of at least three high-frequency pulses, preferably 90 ° high-frequency pulses, is radiated onto the sample. that at least the second high-frequency pulse is set such that the magnetization of the spins of the first group is transferred to the spins of the second group by means of polarization transfer, that after the second high-frequency pulse at least one first gradient dephasing for the spins of the second group Magnetic field pulse is exerted on the sample that at least one further of the high-frequency pulses is set such that the magnetization of the spins of the second group is then transferred back to the spins of the first group by means of polarization transfer and
  • the invention uses a trick by transferring the magnetization of the first group of nuclei of interest to another group of nuclei, namely the second group, for a certain time interval, by polarization transfer, the line of which is located on a different chemical shift in the spectrum, or belongs to another core species.
  • polarization transfer the line of which is located on a different chemical shift in the spectrum, or belongs to another core species.
  • the information of interest namely the magnetization of the nuclei of the first group
  • a range of other chemical shift namely that of the second group
  • the information of interest is in its original Bring back the range of the chemical shift
  • the first group of interest is then rephased (decoded) and the third group of no interest experiences a signal deletion.
  • the use of the gradient magnetic field pulses has the advantage that these so-called "spoil gradients" dephasize the magnetization of the second group of cores after the second high-frequency pulse has been irradiated, so that all phases are evenly distributed in the xy plane .
  • the influence of the aforementioned dephasing of the magnetization of the second group of cores is then reversed by the second rephasing gradient magnetic field pulse (effect on the cores of the third group), which is after the third 90 ° high-frequency pulse.
  • the desired edited signal can be recorded in a single pass, so that motion artifacts, for example, cannot have a disruptive effect.
  • the sample is exposed to a sequence of gradient magnetic field pulses of different coordinate directions in a manner known per se for volume-selective display, and at least three of the high-frequency pulses are set in a disk-selective manner.
  • a further high-frequency pulse preferably a 180 ° high-frequency pulse, which is selective with regard to the chemical shift for the nuclei of the second group, is irradiated.
  • a fourth group of cores which is coupled to the third group, so that the disruptive magnetization of the third group is also transmitted by polarization transfer as a result of the second high-frequency pulse, namely on the fourth group of cores now in place. If, on the other hand, the selective, further high-frequency pulse is radiated in, which, because of its selectivity, only detects the nuclei of the second group, the magnetization of the second group dephases in relation to that of the fourth group in a different way, so that the latter does not transfer to the is transferred back to the third group.
  • the method is carried out on lactate samples. This application is particularly important in biomedicine
  • a high-frequency presaturation pulse which is selective for the cores of the second group and then a gradient magnetic field pulse which dephases these cores is applied to the sample irradiated.
  • the first and the second gradient magnetic field pulses are positioned in the time axis relative to the high frequency pulses in such a way that no stimulated echoes of uncoupled spins are generated.
  • This measure has the advantage that a stimulated echo, namely of unwanted uncoupled spins that could be refocused via the second and third 90 ° high-frequency pulse, is again dephased because such unwanted refocussing only occurs with a symmetrical surface, ie the product from the intensity and length of the gradient magnetic field pulses to the high-frequency pulses could occur.
  • a stimulated echo namely of unwanted uncoupled spins that could be refocused via the second and third 90 ° high-frequency pulse
  • the amount of the high-frequency field strength in the case of the high-frequency pulses does not have a significant effect on the measurement result, but at most causes a certain signal loss, so that the method according to the invention can also be used with surface coils.
  • the time period that is set between the first and the second 90 ° high-frequency pulse and between the third 90 ° high-frequency pulse and the start of the spectra recording is also not critical, because a deviation from the theoretical value 1 / (2J) at AnX system or 1 / (4J) in the An 2 system would only mean a certain signal loss if the transverse relaxation times T2 are much longer than the pulse sequence. With shorter relaxation times T2, however, shorter intervals may be more favorable.
  • an imaging ie a pictorial representation of a two-dimensional or three-dimensional area
  • the method according to the invention can be integrated into known imaging experience, for example in the 2D-FT method with phase and reading gradient or in the back projection method with reading gradient at a variable angle or also in chemical shift imaging, ie spatially resolved spectroscopy with two phase gradients (without reading gradient).
  • a 180 ° high-frequency pulse is radiated onto the sample in the middle between the first and the second high-frequency pulse and after the third high-frequency pulse.
  • This measure has the advantage that the signal intensity is doubled.
  • FIG. 1 is an extremely schematic representation of a
  • FIG. 2 shows an impulse program for explaining an exemplary embodiment of the method according to the invention for a homonuclearly coupled system
  • FIG. 3 shows a representation of a first test sample for verifying the properties of the exemplary embodiment of the method according to the invention
  • FIG. 7 shows an illustration, similar to FIG. 3, but for a different test sample
  • FIG. 11 shows an illustration, similar to FIG. 2, for a variant of the pulse program shown there, with two additional 180 ° pulses;
  • FIG. 12 shows an illustration, similar to FIG. 1, but for a heteronuclearly coupled system
  • FIG. 13 shows a pulse program to explain an exemplary embodiment of the method according to the invention for heteronuclear coupled systems
  • FIG. 14 shows a variant of the pulse program according to FIG. 13;
  • FIG. 17 shows a nuclear magnetic resonance spectrum, similar to FIG. 16, but was recorded according to the inventive method according to FIG. 13.
  • FIG. 1 shows in an extremely schematic manner a nuclear magnetic resonance spectrum of lactate, a system in which a J-coupling between the protons of the CH3 group (A line at 1.35 ppm) and the proton of the CH group (X Line at 4.1 ppm).
  • the A-line of the CH3 group of the lactate is covered by the much more intense B-line of the CH2 group of the surrounding lipid, because biological samples often have a much higher lipid concentration.
  • the method according to the invention is now intended to prepare the A line from the superimposed spectrum by suitable editing.
  • the pulse program shown in FIG. 2 is used for this.
  • the pulse program is used to carry out a volume-selective measurement, it being understood that the method according to the invention is not restricted to volume-selective measurements.
  • the topmost line of the pulse program in FIG. 2 shows high-frequency pulses, which is understood to mean high-frequency signals with a defined envelope contour which are keyed in nuclear magnetic resonance technology.
  • selective and non-selective pulses depending on whether the envelope of the pulses results in a narrow or a wide frequency spectrum.
  • gradient magnetic field pulses G x , G y and Gz are plotted for the three coordinate directions x, y and z.
  • the pulses marked with the symbol “g” in FIG. 2 are so-called “slice gradients”, ie gradient pulses serving to select a spatial slice, while the pulses marked with the symbol “ ⁇ ” represent so-called “trim gradients”, ie the slice gradients gradients preceding or following them, which serve to focus the magnetization.
  • the impulses marked with the symbol "__t” represent so-called “spoil gradients” with which it is possible to dephase or rephase specific magnetizations in a coordinate direction and thus to delete or revive their magnetization as a signal .
  • the gradient magnetic field pulses can be speed and acceleration compensated, as is known per se, for example from US-Z "Journal of Magnetic Resonance", 77 (1988), page 596.
  • a so-called high-frequency presaturation pulse or a corresponding dephasing gradient, or both can first be used in a manner known per se, before the pulse sequence of FIG. 2 begins, in order to magnetize the X group and possible others to delete disturbing signals, such as those from water, so that they can be neglected for the further procedure.
  • the actual method according to the invention begins with a first high-frequency pulse, preferably a 90 ° high-frequency I pulse 10, which is radiated onto the sample in the x direction during the action of a first slice gradient 11 with a subsequent trimming gradient 12.
  • a first high-frequency pulse preferably a 90 ° high-frequency I pulse 10
  • the first 90 ° high-frequency pulse 10 is a so-called soft pulse, which has, for example, an envelope sinx / x and is present in the presence of a magnetic field gradient in x, y or z -Direction disc-selective.
  • the first 90 ° high-frequency pulse 10, like the further 90 ° high-frequency pulses, which will be explained further below, does not act selectively with regard to the chemical shift.
  • the pulse angles of the 90 ° high-frequency pulses are relatively uncritical. In principle, the pulse angle only has to be greater than 0 °.
  • the first "90 °" high-frequency pulse can be set as a so-called "ERNST" angle, which is less than 90 °. This angle allows a fast image sequence for imaging measurements (imaging). It is also possible to replace the first 90 ° high-frequency pulse 10 by a temporally staggered pulse sequence comprising a 90 ° high-frequency pulse and a 180 ° high-frequency pulse which is selective for the A magnetization, in order to avoid interference signals, for example from water, to suppress even better.
  • T.1 arc cot
  • J is, for example, 7.35 Hz, so that the time interval xi is set at 68 ms.
  • a second 90 ° high-frequency pulse 13 is now radiated onto the sample, while a slice gradient 14 or a trimming gradient 15 is simultaneously exerted on the sample in the y direction.
  • the second 90 ° high-frequency I pulse 13 causes the antiphase magnetization of the A group, and only this, to be transferred to the X spins by polarization transfer, which is due to the J coupling between the A group and the X.
  • Group (CH) is possible with a certain chemical shift, while the B magnetization cannot be transferred due to the lack of a corresponding coupling.
  • the (disturbing) B magnetization is transferred to the Y group by polarization transfer when the A magnetization is transferred to the X group.
  • the X-Spins are now also in antiphase to each other.
  • the second 90 ° high-frequency pulse 13 causes the magnetization of the A group - more generally expressed - to be about 1/2 by polarization transfer, 1/4 by double quantum transfer and another 1/4 by zero quantum transfer (at Experiments with heteronuclear coupled spin systems: transferred by multi-quantum transfer).
  • polarization transfer 1/4 by double quantum transfer
  • another 1/4 by zero quantum transfer at Experiments with heteronuclear coupled spin systems: transferred by multi-quantum transfer.
  • the 180 ° RF pulse 16 is selective for the X group, i.e. selective in terms of chemical shift. Thus, if a fourth group Y is present, it does not act on the B magnetization transferred there by polarization transfer.
  • a spoil gradient 17 in the x direction as well as trim and disk gradients 14, 15, 18 in the y direction and a sequence of trim and disk gradients 19, 20 in the z direction are exerted on the sample.
  • the spoil gradient 17 causes a defined dephasing, i.e. a coding of the X magnetization.
  • a third 90 "high-frequency pulse is Pulse 22 radiated onto the sample, which ensures a back polarization of the X magnetization in the area of the A group.
  • the time interval X2 between the second high-frequency pulse 13 and the third high-frequency pulse 22 is set as short as possible.
  • This back-transferred magnetization now evolves in the subsequent Xi interval to an in-phase magnetization, which is recorded and displayed in a recording interval AQ as free induction decay (FID) using known Fourier processing methods from the point in time C at which an echo maximum occurs can. Only the "right" side of the echo, i.e. from time C, added.
  • FID free induction decay
  • a further spoil gradient 23 is applied symmetrically to the third 90 ° high-frequency pulse 22 symmetrically to the spoil gradient 17 in the x direction, as well as a trim gradient 24 in the y direction and a trim gradient 21 in the z direction.
  • FIG. 3 schematically shows a sample 30 in which a ball 31 of approximately 1 cm 3 volume with a mixture of 50% pure acetate and 50% pure lactate is located in an environment 32 made of water.
  • FIG. 6 shows a control measurement in which the volume selectivity of the method according to the invention was checked.
  • the ball 41 consisted of an emulsion of 5% olive oil (with coupled and uncoupled lipids) and 10 mmol lactate.
  • FIG. 8 shows a spectrum which was recorded in a conventional manner with a pulse sequence corresponding to that used in the spectrum of FIG. 4 at 2 T magnetic field strength in a whole-body tomograph during an exposure, and the strong lipid signal can be clearly seen here (CH2 group) at about 1.4 ppm, which covers the lactate signal. At about 0.9 ppm the coupling partner belonging to the CH2 group, the CH3 group, is visible.
  • FIG. 11 shows a variant of the pulse program according to FIG. 2.
  • a 180 ° high-frequency pulse 50 or 51 is in the middle between the first 90 ° high-frequency pulse 10 and the second 90 ° high-frequency pulse 13 or radiated after the third 90 ° high-frequency pulse 22.
  • the time interval between the 180 ° high-frequency pulses 50 and 51 from the preceding 90 ° high-frequency pulses 10 and 22 is therefore x ⁇ / 2.
  • the magnetic field gradient pulses only the Gy gradients are changed, and four spoil gradients 52, 53, 54, 55 can be seen in FIG. 11, which are symmetrical to the first 180 ° high-frequency pulse 50 or symmetrical to the 180 ° Hochfre ⁇ frequency pulse 16 are radiated.
  • the y-slice gradient as slice gradient 56 now lies at the same time as the second slice-selective 180 ° high-frequency pulse 51 and is again followed by a trim gradient 57.
  • the pulse program of FIG. 11 enables the signal intensity to be doubled compared to that in FIG. 2.
  • CYCLPOT cyclic polarization transfer
  • the second 90 ° high-frequency pulse 13 which can have a y-phase or any other phase, effects the polarization transfer, i.e. the transfer of the A magnetization to the X magnetization:
  • the first term corresponds to an X antiphase magnetization.
  • the second term of this expression which corresponds to multi-quantum coherences, is spoiled by the following gradients and can therefore be omitted for the following consideration.
  • the 180 ° high-frequency pulse 16 which is selective with regard to the chemical shift, refocuses only the spins of the X group, that is to say I ⁇ n + i) x, so that the state as it prevailed after the second 90 ° high-frequency pulse 13 is mapped to the state shortly before the third 90 ° high-frequency pulse 22.
  • This third 90 ° high-frequency pulse 22 (y phase) now causes a polarization back transfer of the X magnetization to A magnetization:
  • ⁇ 2 takes into account the dephasing not refocused by the I80 ° high-frequency pulse 16 in the X2 interval.
  • the second term corresponds to multi-quantum coherences that do not lead to observable signals and are therefore omitted.
  • a corresponding consideration can e.g. also for spins with I> i.
  • FIG. 12 shows a representation similar to FIG. 1 of a hetero-nuclear coupled system.
  • a heteronuclearly coupled spin system can be, for example, the spin system of glucose, glycogen or 13 C-enriched naturally occurring substances or medicaments which are of great interest for biomedical research. These systems allow conclusions to be drawn about the metabolism in organic tissue.
  • heteronuclear coupled spin systems can be edited on the proton side, i.e. be prepared, while at the same time the interfering coupled and uncoupled signals are completely suppressed.
  • FIG. 13 corresponds completely to that of FIGS. 2 and 11 with regard to the symbols used, only on the high-frequency side two axes 1 H and 13 C were used for the two types of core.
  • FIGS. 12 and 13 The consideration of FIGS. 12 and 13 is to be undertaken using the example of the 13 C-enriched test substance methanol, an ⁇ 3X system, in which a J coupling between the protons of the CH3 group (A line at 3 ppm) and the 13 C core (X line at 50 ppm).
  • the signal namely the A doublet, is detected on the proton side in this variant of the method, where, owing to the three protons present there, a higher signal intensity occurs than on the 13 C side with the only nucleus present there would.
  • a 180 ° high-frequency pulse 65 which refocuses the X magnetization, is radiated selectively onto 13 C on the 13 C side in the middle of the time between the 90 ° high-frequency pulses 63 and 64.
  • the 13 C spins in the X2 interval are also dephased in the pulse sequence according to FIG. 13 and the protons are rephased in the subsequent time interval X ⁇ .
  • the subsequent time interval X3 is usually as long in time as the first time interval xi.
  • FIG. 13 shows in the x direction that at the time of the first 90 ° high-frequency pulse 60 on the proton side, a slice gradient 66 with a subsequent trim gradient 67 is first applied to the sample.
  • a slice gradient 66 with a subsequent trim gradient 67 is first applied to the sample.
  • two spoil gradients 68, 69 are exerted on the sample symmetrically in time with the 180 ° high-frequency pulse 65, the two spoil gradients 68, 69 being non-polar. Due to the four times smaller gyro-magnetic ratio of 13 C to protons, the gradients in the two interval must be four times larger, which is indicated by the four symbols " ⁇ ".
  • Another spoil gradient 70 is placed on the proton side in the x direction after the third 90 ° high-frequency pulse I 62.
  • a slice gradient 71 and then a subsequent spoil gradient 72 are switched on the proton side at the time of the second 90 ° high-frequency pulse 61, while a trimming gradient 73 is provided in the y direction at the same time as the spoil gradient 70.
  • FIG. 15 finally shows a variant of the pulse sequences of FIGS. 13 and 14, in which, in analog form to the modification of the pulse sequence according to FIG. 11 to that of FIG. 2, two 180 ° high-frequency pulses 80 (disk-selective) and 81 between the first two 90 ° high-frequency pulses 60, 61 or after the third 90 ° high-frequency pulses 62 in order to achieve a signal amplification by a factor of 2 compared to the pulse sequence in FIGS. 13 and 14 .
  • FIG. 16 shows a nuclear magnetic resonance spectrum in which a sample of the type of FIG. 3 was used, in which a sphere surrounded by water with a volume of one cubic centimeter was filled with methanol enriched with 13 C. 16 is recorded with a non-editing three-pulse sequence according to the prior art at a magnetic field strength of 4.7 T during one pass.
  • FIG. 17 shows a nuclear magnetic resonance spectrum that was recorded with a pulse sequence according to FIG. 13. It can be seen that the CH3 signal at 3 ppm (with a double scaling factor) is approximately the same as that in FIG. 16, but the uncoupled spins at 4.7 ppm have practically disappeared.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

Procédé servant à l'enregistrement de spectres de résonance de spins d'échantillons comportant au moins trois groupes de spins. Un premier groupe est couplé à un second groupe, tandis qu'un troisième groupe n'est pas couplé au second, mais présente cependant une position spectrale, par exemple un déplacement chimique, qui concorde uniquement, pour l'essentiel, avec celle du premier groupe. Pour la représentation exclusive du signal du premier groupe, on supprime le signal du troisième groupe. Une séquence de trois impulsions radiofréquence (10, 13, 22) est dirigée sur l'échantillon selon une méthode connue. La deuxième impulsion (13) est réglée de telle manière que l'aimantation des spins du premier groupe est transférée aux spins du deuxième groupe par transfert de polarisation. On applique ensuite à l'échantillon une première impulsion de gradient de champ magnétique (17, 23) à action déphasante sur les spins du deuxième groupe. La troisième impulsion radiofréquence (22) est réglée de telle manière que l'aimantation des spins du deuxième groupe est transférée à nouveau, par un transfert inverse de polarisation, aux spins du premier groupe, qui sont exposés pour finir à une deuxième impulsion de gradient de champ magnétique (23) à action rephasante sur les spins du premier groupe (A).
PCT/DE1990/000309 1989-04-29 1990-04-27 Procede d'enregistrement de spectres de resonance de spins WO1990013826A1 (fr)

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DE59008513T DE59008513D1 (de) 1989-04-29 1990-04-27 Verfahren zur aufnahme von spinresonanzspektren.
EP90906133A EP0422172B1 (fr) 1989-04-29 1990-04-27 Procede d'enregistrement de spectres de resonance de spins

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DEP3914351.1 1989-04-29
DE3914351A DE3914351A1 (de) 1989-04-29 1989-04-29 Verfahren zur aufnahme von spinresonanzspektren

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DE3914301A1 (de) * 1989-04-29 1990-10-31 Bruker Medizintech Verfahren zur aufnahme von spinresoneanzspektren und zur spinresonanz-bildgebung
EP0672916A1 (fr) * 1994-03-16 1995-09-20 Spectrospin Ag Contrôle selectif du transfert de magnétisation dans des systèmes d'échange à plusieurs positions
WO2001073479A1 (fr) * 2000-03-29 2001-10-04 The Regents Of The University Of California Spectroscopie par resonance magnetique bidimentionnelle correlee localisee du cerveau humain a decalage
DE10108341C1 (de) * 2001-02-21 2002-09-12 Siemens Ag Magnetresonanz-Spektroskopieverfahren mit einem Variieren von Phasen von HF-Pulsen
US8970217B1 (en) 2010-04-14 2015-03-03 Hypres, Inc. System and method for noise reduction in magnetic resonance imaging
US20180220949A1 (en) * 2017-02-08 2018-08-09 Pablo Jose Prado Apparatus and method for in-vivo fat and iron content measurement
CA3168472A1 (fr) * 2018-09-14 2020-03-19 10250929 Canada Inc. Methode et systeme de mesure in vivo et non invasive de niveaux de metabolites

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US4701708A (en) * 1986-08-01 1987-10-20 General Electric Company Polarization transfer by selective homonuclear technique for suppression of uncoupled spins in NMR spectroscopy
EP0347990A1 (fr) * 1988-06-22 1989-12-27 Koninklijke Philips Electronics N.V. Procédé et dispositif de détermination d'un spectre RMN au moyen d'impulsions sélectives de transmission de polarisation

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Title
Journal of Magnetic Resonance, Band 76, Nr. 2, 1. Februar 1988, Academic Press, Inc., (Duluth, MN, US), L.O. SILLERUD et al.: "(13C)-Polarization Transfer Proton NMR Imaging of a Sodium (13C) Formate Phantom at 4.7 Tesla", seiten 380-385 *
Magnetic Resonance in Medicine, Band 3, Nr. 1, Februar 1986, Academic Press, Inc., (New York, US), C.L. DUMOULIN: "Suppression of Water and Other Noncoupled Spins by Homonuclear Polarization Transfer in Magnetic Resonance Imaging", seiten 90-96 *
Magnetic Resonance in Medicine, Band 9, Nr. 2, Februar 1989, Academic Press, Inc., (Duluth, MN, US), A. KNUTTEL et al.: "Single-Scan Volume-Selective Spectral Editing by Homonuclear Polarizaton Transfer", seiten 254-260 *

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EP0422172A1 (fr) 1991-04-17
US5172060A (en) 1992-12-15
DE3914351C2 (fr) 1993-05-19
JPH03505694A (ja) 1991-12-12
EP0422172B1 (fr) 1995-02-22
DE59008513D1 (de) 1995-03-30
DE3914351A1 (de) 1990-10-31

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